Search PubMed⌕ Search

Biomedical subjects

B K Evans

Publications and source records attributed to B K Evans.

At least 55 records · Page 3Linked to original sources
PubMed1985

Absorption of delayed-release prednisolone in ulcerative colitis and Crohn's disease.

The absorption and urinary excretion of [3H]prednisolone after oral ingestion was examined using hard gelatin capsules with and without a coating of Eudragit-S which delayed release of the contents. In 6 patients with ulcerative colitis absorption was delayed until the preparation reached the colon but the total absorption was unchanged. In 6 patients with Crohn's disease and ileal strictures the preparation broke proximal to the stricture and absorption was delayed until this occurred (within 4-12 h). In 5 patients with Crohn's disease and intestinal resections the capsules broke unreliably.

Adult↗
PubMed1985

Innervation of bat heart: cholinergic and adrenergic nerves innervate all chambers.

Adult Miniopterus schreibersii were anesthetized with chloroform, and in vitro preparations of cardiac chambers were prepared. Stimulation of intramural nerves in right ventricles paced at 6 Hz caused an inhibition (56.3 +/- 3.5% decrease on basal force) mediated by cholinergic nerves and an excitation (91.5 +/- 9.9% increase on basal force) mediated by adrenergic nerves. Mean pD2s (-log effective concentration, 50%) for ventricular beta-adrenoceptors and muscarinic cholinoceptors were 6.99 +/- 0.03 and 6.42 +/- 0.07, respectively. The inhibition of ventricular contractility, by nerve stimulation or exogenous acetylcholine, occurred even after blockade of beta-adrenoceptors. The results were comparable to those obtained on atria. In some experiments, the heart was perfused in situ and paced via electrodes on the ventricle: stimulation of the right vagus nerve decreased right ventricular contractility by up to 90%. The results show that, at least in this hibernating mammal, there is an adrenergic innervation of the ventricle. The presence of a cholinergic vagal innervation capable of inhibiting the basal force of ventricular contraction has not been shown in any other mammal.

Animals↗
PubMed1984

Comparison of the absorption and metabolism of sulphasalazine and acrylic-coated 5-amino salicylic acid in normal subjects and patients with colitis.

Serum levels of 5-amino salicylic acid ( 5ASA ) and acetyl 5ASA have been measured in volunteers after ingestion of sulphasalazine (6 g) and compared with levels after an equivalent dose of acrylic coated 5ASA (2.4 g). The serum levels of both 5ASA and acetyl 5ASA were similar after each preparation apart from an early peak of 5ASA following acrylic coated 5ASA . Serum and urinary levels for 5ASA and acetyl 5ASA have been measured in colitic patients following equivalent doses of sulphasalazine and acrylic coated 5ASA . Serum levels were similar; 25% of the calculated ingested 5ASA was excreted in the urine after sulphasalazine compared with 20% following acrylic coated 5ASA .

Adult↗
PubMed1983

Colonic release of 5-amino salicylic acid from an oral preparation in active ulcerative colitis.

5-amino salicylic acid coated with acrylic based resin was given orally to eight patients with active ulcerative colitis. Abdominal X-rays confirmed that the preparation released its contents in the terminal ileum and proximal colon. Differences between individuals were marked; the plasma 'concentration-time profile' reflected variations in the time taken for tablets to reach the terminal ileum.

Adult↗
PubMed1983

Use of enzyme immunoassays and the latex agglutination test to measure the temporal appearance of immunoglobulin G and M antibodies after natural infection or immunization with rubella virus.

The time course of appearance of antibodies after infection with rubella virus was determined with an immunoglobulin G (IgG) detection enzyme-linked immunosorbent assay, a latex agglutination test, and an IgM detection enzyme-linked immunosorbent assay. In six naturally infected rubella patients and 26 vaccinees, antibodies measured by either the IgG enzyme-linked immunosorbent assay or the latex agglutination test generally appeared in parallel with those detected by the hemagglutination inhibition test. By 28 days after inoculation of live virus vaccine and by 2 days postonset of clinical rubella symptoms caused by natural infection, antibodies were found by the two tests for all individuals. A commercially available enzyme-linked immunosorbent assay kit was used to detect rubella-specific IgM. After natural infection, IgM appeared earlier than IgG, and although IgM titers decreased rapidly postinfection, in four of five patients antibodies were still detectable 40 to 43 days after the onset of clinical symptoms. After vaccine-induced infection, rubella-specific IgM was lower in titer than after natural infection and was detected in only three of seven vaccinees 70 days post-immunization.

Adult↗
PubMed1982

An oral preparation to release drugs in the human colon.

1 A colonic delivery system is described to deliver orally ingested drugs to the colon and release them at that site by coating with an acrylic based resin (Eudragit S). The technique is validated using X-ray evidence and serum levels of a convenient marker, sulphapyridine. 2 This colonic delivery system is particularly suitable for drugs such as 5-amino salicylic acid or steroids in the management of patients with colitis.

Aminosalicylic Acids↗
PubMed1982

Comparison of the latex agglutination test with the hemagglutination inhibition test, enzyme-linked immunosorbent assay, and neutralization test for detection of antibodies to rubella virus.

The ability of a rapid, latex agglutination test to diagnose rubella infection and to measure immune status was evaluated by comparison with the hemagglutination-inhibition (HAI) test, enzyme-linked immunosorbent assay (ELISA), and the neutralization (NT) test. The latex agglutination test accurately detected serological conversions in 74 pairs of sera representing 21 natural infections and 53 immunizations. The antibody levels of 276 sera from the general population were determined by latex agglutination, HAI, and ELISA. The correlation coefficients between the titers obtained by HAI and latex agglutination and by ELISA and latex agglutination were statistically significant. Results on 12 sera did not agree when measured by the three tests. These sera were included among the 196 specimens tested by NT. The correlation coefficient between NT and latex agglutination titers was statistically significant. There was one serum positive by latex agglutination but negative by NT, and five sera were negative by latex agglutination but had titers of 4 to 8 in the NT. The relative sensitivity of detecting antibody was greater by latex agglutination than by HAI. An additional 49 sera containing residual nonspecific hemagglutinin inhibitors were evaluated by latex agglutination and NT. The untreated sera showed no false positive reactions, and 36 of 39 NT positive sera were positive in the latex agglutination test.

Antibodies, Viral↗
PubMed1982

Guaiacol -- a new compound in the treatment of gastro-oesophageal reflux?

The effects on the oesophagus of an aromatic oil, guaiacol, has been examined in a group of 20 patients with reflux oesophagitis and also normal volunteers. This agent produced a rapid and sustained rise in resting lower oesophageal sphincter pressures and the peristaltic pressures induced in response to swallowing liquids. This compound may prove useful in the treatment of patients with reflux oesophagitis and other disorders of oesophageal motility.

Esophagitis, Peptic↗
PubMed1981

Baroreceptor control of heart rate in the conscious toad Bufo marinus.

Perivascular balloons were used to elicit heart rate (HR) responses to imposed changes in mean arterial pressure (Pa) in conscious unrestrained toads (Bufo marinus). It is clear that functional baroreceptors lie in the pulmocutaneous arteries of B. marinus, and that these can elicit compensatory heart rate responses to perturbations of blood pressure. Functional baroreceptors were not present in the carotid circulation and are probably absent from the lateral aortae and conus arteriosus as well. Normalized gain of the baroreceptor-heart rate reflex (delta HR%/delta Pa) in five toads was 13%/kPa, which is considerably less than that found in other vertebrates to date.

Animals↗